Electrospun 1D Al-LLZO incorporated PVDF-HFP composite electrolyte with fast Li plus pathway derived from highway-traction effect for high performance lithium metal batteries

초록

The transition from the use of liquid electrolytes to solid-state electrolytes in lithium metal batteries is expected to bring significant benefits such as enhanced energy density. Despite the advantages, the formation of Li dendrites during the Li plating/stripping process remains a drawback, which leads to internal short circuits and potential battery explosions. To address these issues, a solid electrolyte with a high Li+ transference number is crucial for suppressing dendritic growth through uniform Li+ deposition. In this study, we introduce a composite solid electrolyte (CSE) comprising PVDF-HFP with 1D electrospun Al-doped LLZO nanofibers and succinonitrile as a plasticizer. The dispersed nanofibers create continuous Li+ transport channels, while succinonitrile enhances the Li+ kinetics via its polar nitrile functional group, resulting in a high ionic conductivity (3.26 x 10-4 S cm-1) and lithium transference number (0.78). With the proposed electrolyte, a Li|Li cell is prepared, exhibiting a low and stable overpotential for over 1000 h, indicating excellent interfacial stability. Further, the CSE helps produce an exceptional cycling performance with a capacity retention of 83 % after 1000 cycles at 5C in Li|LiFePO4 full cells. This advanced electrolyte system has significant potential to enhance the performance and safety of future energy storage technologies.

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